US1014435A - Safety-valve. - Google Patents

Description

J1 AULD & J. GRAHAM.

SAFETYv VALVE.

APPLIOATION FILED 1123.211911.

1,014,435. Patented Jam.v 9, 1912.

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J. AULD & J. GRAHAM.

SAFETY VALVE.

APPLICATION FILED 111111.25, 1911.

Patented J an. 9, 1912.

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SAFETY VALVE.

J. AULD & J. GRAHAM.

APPLIUATION FILED APB..25,1911. 1,014,435.

J. AULD @L J. GRAHAM.

SAFETY VALVE.

APPLICATION FILED APR.25, 1911.

1,014,485. l Patented JaI1.9, 1912. K

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JOHN AULD AND JOHN GRAHAM, 0F GLASGOW, SCTLAND.

SAFETY-VALVE.

Specification of Letters Batent.

Application filed April 25, 1911.

Patented Jan. 9,1912.

Serial No. 623,249.

To all 'whom t may concern Be it known that we, JOHN AULD and JOHN GRAHAM, both subjects of the King of Great Britain and Ireland, and residing at Glasgow, Scotland, engineers, have invented new and useful Improvements in Safety Valves, of which the following is a specification.

Our invention relates to improvementsv in and relating to safety valves for steam boilers and the like, of the class in which after thev main valve has opened in the usual way,

by the increase of steam pressure over that arranged for, or has been assisted to open by an auxiliary valve, the main valve is lifted or opened beyond what is usually the normal lift of boiler safety valves to allow of a fuller escape of the steam, which has been effected by providing an auxiliary valve,l which may be so loaded as to open a little later than the main valve, to regulate the supply of steam to a loose or floating piston arranged to act on the main valve to give it the increased lift desired.

In order that our invention may be properly understood we have hereunto appended three sheets of' explanatory drawings in` Which- Figures 1 and 2 on Sheet 1 are respec-- tional view of a modified form of auxiliary valve which we employ.

Referring to these drawings z-in carrying this invention into effect or practice, according to one modification as illustrated by Figs. l and 2, the inlet a leads the steam to the underside of the main valve b and by the passage c to the underside of the auxiliary valve d which when open allows the steam to act on the underside of the piston e placed loose on the valve spindle f, as shown. The main valve spindle or rod f passes through the center of the loosely fitted piston e and is continued through the chamber g into the atmosphere where it -may be` loaded in the usual manner by the spring z, by deadweights or otherwise as may be found desirable. The auxiliary valve d which is balanced on the outlet side by a piston j may also be loaded in any suitable manner, by the spring z' or otherwise. Any steam passing the balancing piston y" escapes into the atmosphere by ports or ducts la. Any steam passing the loosely litting piston e escapes through the port or lduct l into outlet branch m. i v

As illustrated by Fig. 3, the piston c, in stead of Working within the close cylinder forming the chamber g is inverted and has its annular wall e1 made deeper, so as to enable it to work outside the annular wall g1 of the cylinder, or inside of same as shown in Fig. 4. The arrangements of the main valve andthe auxiliary valve l are similar to those already described. y The action is as follows.:-When the main valve and auxiliary valve d Yare loaded respectively so as to open on the steam boiler, steam main-'or other vessel attaining a given pressure, the steam pressure under main valve b would open up said valve and the surplus steam escaping would be discharged through outlet branch m. The highpressure steam in inlet branch a passing up the duct 0 to the underside-of auxiliary valve al also opens up said valve and the Steam thence flowing through port n accumulates pressure under the loose piston e which iioats up against under face of collar o exerting such a lifting force as to further com.- press main loading spring hand give in consequence an increased lift to; the main valve b over and above the limited opening due merely to the pressure acting under same. Any accumulation of pressure under the loose piston e which occurs when the valve is in operation and would tend to exert a back pressure on auxiliary valve d is balanced by the balancing'piston j attached to auxiliary valve.

'Ihe objectin having piston e loose on the valve spindle 7" is to overcome the danger involved in having pistons xed topvalve spindles by which arrangement if the piston jams the safety valve becomes inoperative. On the other hand should the loose piston e jam circumferentially the safety valve will operate independently but with the reduced lift, similar in fact to ordinary standard safety valves. The hole through the center of loose piston e is bored with an ample amount of clearance over and above the thickness of valve spindle f. It will be evident that any suitable form of auxiliary valve for passing steam to the underside of the piston may be employed such as a valve iittedat the lower end of'its s indie with a balancing piston and elastic diaphragm, in which case the steam would not be allowed to escape to the atmosphere. In this case, as shown in Fig. 6, the steam from the boiler passes by the duct c to the upper side of the i valve d which opens when the steam pressure is above a predetermined height, andi the steam passes through the duct a to the under side of the loose pistone. Such safety 1 valves may be so arranged that one auxiliary valve may operate a nest or two, three or more main safety valves, each main .safetyY valve being fitted with its ownloose piston.

Fig. 5 on Sheet 3 illustrates another arrangement whereby the loose or iioating piston e is placed under the main valve b but is not attached thereto.

ject of balancing`piston p is to maintain a constant operatlve pressure on auxiliary valve d as pressure varies in cylinder g with 1 the opening and closing of valve d. rI`he piston j balances any .back pressure on valve d. On the steam pressure attaining the maximum pressure it opens up the valve b and also auxiliary valve el. On the auxil iary valve d being opened the steam in cyl- 1 inder g over loose piston e is discharged into g the atmosphere through the out-let branch.

by the standards .s and so obtain a freer and fuller discharge of surplus steam. On the pressure diminishing in steam boiler the regulating or auxiliary valve d shuts down and pressure being equalized on both sides of loose piston e it drops away from contact with the main valve b which is closed by its loading spring h shutting it down.

vW'hat we do claim as our invention and desire to secure by Letters Patent, is

1. The combination of a valve casing having an inlet and outlet port, a main valve for closing and affording communication between the outlet and inlet ports, an auxiliary valve having a passage leading from the inlet port, and means adjacent to and In this ar-,. rangement the initial pressureenters by g branch a to underside .of main valve t' and; by duct c to underside of loose piston e and `underside of balancing piston p. The ob;

operable upon the main valve, said means being affected by the opening of the auxiliary valve to increase the amount of opening of the main valve.

2. rlhe combination of a valve casing having an inlet and outlet port, 'a main valve for closing or affording communication between the outlet and inlet ports, a loose piston mounted on the main valve. stem, an

Aauxiliary valve having a passage leading from the inlet port, said casing having a passage extending from the auxiliary valve to the loose piston, said loose piston being aiected by pressure when the auxiliary valve is opened to increase the amount of opening of the main valve.

3. The combination of a valve casing for rsteam boilers or the like, having an inlet and an outlet port, a'main valve for closing or affording communication between the outlet and inlet ports, means operative on the main valve stem to normally prevent communication between the inlet and outlet ports, a piston loosely mounted in a guideway adjacent to the main valve stem, said casing having a passage leading from the inlet port to a point adjacent the loose piston, an auxiliary valve stem, means operative upon the said auxiliary valve stem to normally close the passage, the main and auxiliary valve stems being automatically unseated by an abnormal pressure, said un'- seating of the auxiliary valve stem tending to actuate the loose piston to increase the amount of opening of the main valve stem.

4:. The combination of a valve casing for steam boilers or the like, having an inlet and an outlet port, a main valve for closing or affording communication between the outlet and inlet ports, means operative on the main valve stem." to normally prevent communication between the inlet and outlet ports, a piston loosely mounted in a guideway adjacent the main valve stem, said casing having a passage leading from the invlet port to a point adjacent the loose piston, an auxiliary valve stem, said casing also vhaving a chamber formed therein and a duct leading from the chamber to the atmosphere, a balanced piston on the auxiliary valve stem andy movable in said chamber, means operative upon the said auxiliary valve stem to normally close the passage, the main and auxiliary valve stems being automatically unseated by an abnormalv pressure, said unseating of the auxiliary valve stem tending to actuate the loose piston to piston, a loaded auxiliary regulating Valve, names to this specification, in the presence a balancing piston connected to the auxiliary of two subscribing witnesses.

i valve, and steam passages leading to the JOHN AULD,

underside of auxiliary Valve and through it JOHN GRAHAM. to the underside of operating piston sub- Witnesses: stantially as set forth. JOHN SIME,

In testimony whereof,` We have signed our THOMAS BENNIE BRoWNLIE.

Copies of this patent may be obtained for ve 'cents each, by addressing the Commissioner of Patents. Washington, D. C.

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